040_Eureka 服務註冊與發現

• 2022 年 3 月 22 日
• 筆記
• 170_SpringCloud

什麼是Eureka

原理講解

Eureka的基本架構

三大角色

盤點目前工程狀況

創建Eureka服務端子模組 springcloud-eureka-7001

導入依賴 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="//maven.apache.org/POM/4.0.0"
         xmlns:xsi="//www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="//maven.apache.org/POM/4.0.0 //maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud</artifactId>
        <groupId>com.qing</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-eureka-7001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--服務提供者使用eureka，eureka服務端使用eureka-server-->
        <!-- //mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
        <!--熱部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>

    </dependencies>

</project>

配置文件 application.yml

server:
  port: 7001

# Eureka配置
eureka:
  instance:
    hostname: localhost # Eureka服務端的實例名稱
  client:
    register-with-eureka: false # 表示是否向eureka註冊中心註冊自己，這是eureka服務端不需要註冊，其他服務需要註冊為true
    fetch-registry: false # 如果為false，表示這是註冊中心，其他服務需要為true
    service-url: # 註冊url，監控頁面是：//${eureka.instance.hostname}:${server.port}
      defaultZone: //${eureka.instance.hostname}:${server.port}/eureka/

源碼：

啟動類，添加開啟Eureka服務端註解

package com.qing.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer // 開啟Eureka服務端
public class EurekaServer_7001 {
    public static void main(String[] args) {
        SpringApplication.run(EurekaServer_7001.class, args);
    }
}

啟動測試

監控頁面：//${eureka.instance.hostname}😒{server.port}
//localhost:7001

服務提供者子模組 springcloud-provider-dept-8001

pom.xml添加Eureka依賴

<!--服務提供者使用eureka，eureka服務端使用eureka-server-->
<!-- //mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
    <version>1.4.6.RELEASE</version>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="//maven.apache.org/POM/4.0.0"
         xmlns:xsi="//www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="//maven.apache.org/POM/4.0.0 //maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud</artifactId>
        <groupId>com.qing</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept-8001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--springcloud-api模組，實體類-->
        <dependency>
            <groupId>com.qing</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--jetty-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <!--熱部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <!--服務提供者使用eureka，eureka服務端使用eureka-server-->
        <!-- //mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>

    </dependencies>

</project>

application.yml添加Eureka配置

server:
  port: 8001

mybatis:
  type-aliases-package: com.qing.springcloud.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
# 開啟駝峰
#  configuration:
#    map-underscore-to-camel-case: true

spring:
  application:
    name: springcloud-provider-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: org.gjt.mm.mysql.Driver
    url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

# Eureka
eureka:
  client:
    service-url:
      defaultZone: //localhost:7001/eureka/ # 使用Eureka服務端配置的註冊url

源碼：

啟動類中，添加開啟Eureka服務註解

package com.qing.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * 啟動類
 */
@EnableEurekaClient // 在服務啟動後自動註冊到Eureka中
@SpringBootApplication
public class DeptProvider_8001 {
    public static void main(String[] args) {
        SpringApplication.run(DeptProvider_8001.class, args);
    }
}

啟動測試

註：先啟動Eureka服務端，再啟動服務提供者

完善Eureka監控資訊 Actuator

pom.xml添加依賴

<!--完善Eureka監控資訊 actuator-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="//maven.apache.org/POM/4.0.0"
         xmlns:xsi="//www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="//maven.apache.org/POM/4.0.0 //maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud</artifactId>
        <groupId>com.qing</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept-8001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <!--springcloud-api模組，實體類-->
        <dependency>
            <groupId>com.qing</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--jetty-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <!--熱部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <!--服務提供者使用eureka，eureka服務端使用eureka-server-->
        <!-- //mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
        <!--完善Eureka監控資訊 actuator-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

    </dependencies>

</project>

application.yml配置：監控資訊 actuator-info

server:
  port: 8001

mybatis:
  type-aliases-package: com.qing.springcloud.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
# 開啟駝峰
#  configuration:
#    map-underscore-to-camel-case: true

spring:
  application:
    name: springcloud-provider-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: org.gjt.mm.mysql.Driver
    url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

# Eureka
eureka:
  client:
    service-url:
      defaultZone: //localhost:7001/eureka/ # 使用Eureka服務端配置的註冊url

# 監控資訊 actuator-info配置
info:
  app.name: qing-springcloud
  company.name: 清風閣

開啟測試

配置前：

配置後：

application.yml配置：修改Eureka監控頁面上服務默認描述

server:
  port: 8001

mybatis:
  type-aliases-package: com.qing.springcloud.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
# 開啟駝峰
#  configuration:
#    map-underscore-to-camel-case: true

spring:
  application:
    name: springcloud-provider-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: org.gjt.mm.mysql.Driver
    url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

# Eureka
eureka:
  client:
    service-url:
      defaultZone: //localhost:7001/eureka/ # 使用Eureka服務端配置的註冊url
  instance:
    instance-id: springcloud-provider-dept-zdy # 修改Eureka監控頁面上服務默認描述
# 監控資訊 actuator-info配置
info:
  app.name: qing-springcloud
  company.name: 清風閣

修改前：

修改後：

服務發現：獲取其他微服務資訊

編寫程式碼

package com.qing.springcloud.controller;

import com.qing.springcloud.pojo.Dept;
import com.qing.springcloud.service.DeptService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * 提供服務
 */
@RestController
public class DeptController {

    @Autowired
    private DeptService deptService;
    @Autowired
    private DiscoveryClient client;

    @PostMapping("/dept/add")
    public boolean add(Dept dept) {
        return deptService.add(dept);
    }

    @GetMapping("/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id) {
        return deptService.queryById(id);
    }

    @GetMapping("/dept/listAll")
    public List<Dept> listAll() {
        return deptService.queryAll();
    }

    @GetMapping("/dept/discovery")
    public Object discovery() {
        // 獲取微服務列表的清單
        List<String> services = client.getServices();
        System.out.println("discovery=>services:" + services);
        // 得到一個具體的微服務資訊，通過微服務的applicationName獲取
        List<ServiceInstance> instances = client.getInstances("springcloud-provider-dept");
        for (ServiceInstance instance : instances) {
            System.out.println(
                    "serviceId=》" + instance.getServiceId() + "\n"
                    + "host=》" + instance.getHost() + "\n"
                    + "port=》" + instance.getPort() + "\n"
                    + "uri=》" + instance.getUri() + "\n"
                    + "instanceId=》" + instance.getInstanceId() + "\n"
            );
        }
        return this.client;
    }
}

啟動類，添加開啟服務發現的註解

package com.qing.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * 啟動類
 */
@EnableDiscoveryClient // 開啟服務發現
@EnableEurekaClient // 在服務啟動後自動註冊到Eureka中
@SpringBootApplication
public class DeptProvider_8001 {
    public static void main(String[] args) {
        SpringApplication.run(DeptProvider_8001.class, args);
    }
}

啟動測試

自我保護機制